A Concept of Precise VLBI/GNSS Ties with Micro-VLBI

Petrov, Leonid; York, Johnathan; Skeens, Joe; Ji-Cathriner, Richard; Munton, David; Herrity, Kyle

doi:10.1007/1345_2023_211

Cited by 3 publications

(1 citation statement)

References 8 publications

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“…As discussed in more detail in Petrov et al. (2023), vector ties generated with VLBI directly relate the microwave phase reference points. This direct measurement overcomes the difficulty in conventional optical surveying that models must relate the surveyed positions to the true electrical phase center with some associated errors.…”

Section: Introductionmentioning

confidence: 99%

First Observations With a GNSS Antenna to Radio Telescope Interferometer

Skeens,

York,

Petrov

et al. 2023

Radio Science

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We describe the design of a radio interferometer composed of a GNSS antenna and a VLBI radio telescope. Our eventual goal is to use this interferometer for geodetic applications including local tie measurements. The GNSS element of the interferometer uses a unique software‐defined receiving system and modified commercial geodetic‐quality GNSS antenna. We ran three observing sessions in 2022 between a 25 m radio telescope in Fort Davis, Texas (FD‐VLBA), a transportable GNSS antenna placed within 100 meters, and a GNSS antenna placed at a distance of about 9 km. We have detected a strong interferometric response with a Signal‐to‐Noise Ratio (SNR) of over 1000 from GPS and Galileo satellites. We also observed natural radio sources including Galactic supernova remnants and Active Galactic Nuclei (AGN) located as far as one gigaparsec, thus extending the range of sources that can be referenced to a GNSS antenna by 18 orders of magnitude. These detections represent the first observations made with a GNSS antenna to radio telescope interferometer. We have developed a novel technique based on a Precise Point Positioning (PPP) solution of the recorded GNSS signal that allows us to extend integration time at 1.5 GHz to at least 20 minutes without any noticeable SNR degradation when a rubidium frequency standard is used.

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Section: Introductionmentioning

confidence: 99%

First Observations With a GNSS Antenna to Radio Telescope Interferometer

Skeens,

York,

Petrov

et al. 2023

Radio Science

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Simulating VLBI observations to BeiDou and Galileo satellites in L-band for frame ties

Schunck,

McCallum,

Calves

2024

Journal of Geodetic Science

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Using the very long baseline interferometry (VLBI) technique to observe Earth-orbiting satellites is a topic of increasing interest for the establishment of frame ties. We present a simulation study on VLBI observations to BeiDou and Galileo satellites in L-band to investigate the accuracy of inter-technique frame ties between VLBI and global navigation satellite system (GNSS). We employ a global network of 16 antennas equipped with dedicated L-band receivers capable of observing BeiDou’s B1 and B3 navigation signals and Galileo’s E1 and E6 navigation signals. Through extensive Monte Carlo simulations, we simulate 24-h sessions to determine the optimal ratio of satellite to quasar scans. The optimal schedule uses about 80–90% satellite sources. We find that the 10–20% observations of quasar sources improve the estimation of the troposphere and, consequently, the estimation of the antenna position. Combining the normal equations from seven 24-h sessions, we derive a 7-day solution. The average antenna position repeatability is 7.3 mm. We identify the limitations of the results as the tropospheric turbulence, inaccuracies in the satellite orbit determination, and the lack of a more homogeneously distributed global network. This simulation study supports the understanding in the topic of building a frame tie using VLBI observations to GNSS satellites.

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Effect of station selection on VLBI-to-GNSS orientation transfer using space-ties onboard a next generation Galileo satellite

Sert,

Hugentobler,

Karatekin

et al. 2024

Preprint

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Each geodetic technique realizes its specific reference frame and traditionally these independent frames are linked through the local-ties at collocation sites. Space ties onboard of a spacecraft can be also used to connect different frames as another complementary approach. Observations of a broadband VLBI transmitter (VT) onboard Galileo satellite by a VLBI ground station network can create such a link between GNSS and VLBI reference frames. In this study, we simulate observations of a VT onboard Galileo satellites and investigate the effect of VT observing network/station selection on the rotation transformation parameters between the VLBI and GNSS frames. We find that the rotation transformation uncertainties can be inflated by more than 25% when a geometrically critical station is removed from the network of 21 ground stations. We additionally analyze various VLBI networks consisting of 8-9 ground stations dedicated to IVS R1/R4 sessions. We report that by adding individual stations into some networks uncertainties are reduced by up to a factor of three in daily solutions and up to 50% for all orientation components when combining solutions covering a Galileo repeat cycle of ten days.

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A Concept of Precise VLBI/GNSS Ties with Micro-VLBI

Cited by 3 publications

References 8 publications

First Observations With a GNSS Antenna to Radio Telescope Interferometer

First Observations With a GNSS Antenna to Radio Telescope Interferometer

Simulating VLBI observations to BeiDou and Galileo satellites in L-band for frame ties

Effect of station selection on VLBI-to-GNSS orientation transfer using space-ties onboard a next generation Galileo satellite

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